v1.0.0 Open source · MIT · ASCII or HTML · no probing

Topology discovery, as ASCII or as a real diagram.

Walks the network from a vantage host, builds the connection graph, renders it as ASCII for the terminal or as interactive HTML for sharing. Useful before you have a HostAtlas account; useful next to one when you do.

$ curl -fsSL https://tools.hostatlas.app/install.sh | sh -s atlasmap copy

Or via brew: brew install hostatlas-labs/tap/atlasmap · source on GitHub.

MIT

licensed

ASCII

+ HTML · Mermaid · DOT

~500

hosts tested

atlasmap · keywest scan · ascii

$ atlasmap scan keywest --output ascii --include outbound
→ walking netns · resolving DNS · matching providers…

[keywest] ──┬── [db-prod-01] 5432/tcp postgres
│
├── [cache-2.eu] 6379/tcp redis
│
├── [worker-1..4] 5672/tcp rabbitmq
│
└── [internet] 443/tcp outbound
├── stripe.com last 14s ago
├── api.openai.com last 4s ago
└── 3.5.0.0/16 (s3.amazonaws · last 41s)

→ 8 nodes · 11 edges · saved keywest-2026-05-15.html _

— Why a map matters

You can’t reason about traffic you can’t see.

A diagram is the cheapest review tool in ops. Atlasmap turns the network into something you can show your team without setting up a wiki.

new infra needs a map

When you inherit infra — new job, post-acquisition, take over from someone — the first thing you want is a picture. Atlasmap produces one with one command.

outbound matters too

"Where is this calling out to" is half the security review. Atlasmap surfaces outbound dependencies; most tools only show inbound.

ASCII shares cleanly

A diagram you can paste into a Slack message is more useful than a 4 MB PNG. ASCII output is a first-class format, not an afterthought.

— How it works

Six capabilities. One binary.

connection walk

ss + /proc/net + reverse DNS. Each socket gets mapped to a name + remote — no port scanning, no probing.

ASCII tree

For terminal + chat sharing. Optional 256-color or truecolor when the terminal supports it.

interactive HTML

Self-contained single-file HTML with pan + zoom + click-to-detail. No server, no external JS, opens in any browser.

Mermaid + DOT export

For embedding in Confluence / GitHub markdown / Jira / your favourite diagram tool. The graph survives a copy-paste.

multi-host

Run from one vantage; pull connection data from others over SSH. Merges into one map with per-host accents.

per-edge labels

Protocol, port, last-seen timestamp, traffic bytes (where available). The graph carries enough context to actually use it.

— Honest answers

Common questions.

Does it scan remote hosts?

No — it reads what each host already knows about its own connections. No port scanning, no probing, no AWS-bill-blowing-up.

Big fleets?

Tested at ~500 hosts. Beyond that the platform-side Atlas Graph is the better tool — continuous, alert-aware, query-able.

Outbound to where?

When the destination is in DNS, you get a name. Otherwise an IP. Cloud-provider IP ranges resolved to provider names where the public range table covers them.

License?

MIT. Use commercially, modify, redistribute. The HTML export carries the same licence.

Discovery & Mapping

For developers